Bacterial meningitis and pneumococcal serotype distribution in children in cameroon

Prevalence, aetiology, vaccination coverage and spatio-temporal pattern among patients admitted with acute bacterial meningitis to the sentinel hospital surveillance network in Yemen, 2014-20, before and during the civil war

BACKGROUND

Acute bacterial meningitis (ABM) is a serious health issue in Yemen where civil war, which continues unabated, has crippled the healthcare system. We conducted a nationwide retrospective observational study in Yemeni sentinel hospitals to identify the prevalence, aetiology, vaccination coverage and spatio-temporal pattern of ABM in children aged <5 years before and during the civil war, 2014-20.

METHODS

Cerebrospinal fluid samples were collected from hospitalized children and were analysed macroscopically for appearance and microscopically by Gram stain and white blood cell count. Culture and latex agglutination tests were performed. Data on the prevalence of and vaccination coverage for ABM were obtained from the Ministry of Health. Joinpoint regression was used to assess the annual percent change (APC) of ABM prevalence and vaccination coverage. Pearson's correlation was used to evaluate the association between ABM prevalence and vaccination coverage.

RESULTS

In total, 11 339 hospitalized children had suspected cases of ABM (prevalence, 40.07/100 000 of the whole Yemeni population) and 2.6% (293/11 339) of suspected ABM cases were confirmed (prevalence, 1.04/100 000 of the whole Yemeni population). The dominant pathogens were Streptococcus pneumoniae, Neisseria meningitidis and Haemophilus influenzae type b (Hib). The civil war reduced the Hib and pneumococcal vaccination coverage (APC = -1.92), reaching its lowest (79.5%) in 2018. The prevalence of suspected ABM increased (APC = 3.46), reaching its maximum (6.08/100 000 of the whole Yemeni population) in 2019. The conflict inversely correlated with the ABM prevalence and vaccination coverage (Pearson correlation coefficient (r), -0.69 to -0.53). Ta'izz region, which was severely affected by the civil war, had the highest prevalence of suspected ABM (120.90/100 000 of the whole Yemeni population) and lowest vaccination coverage (60%).

CONCLUSIONS

The civil war had a negative impact on vaccination coverage and coincided with increasing prevalence of ABM in Yemen. Streptococcus pneumoniae is the dominant causative pathogen.

Antimicrobial Resistance Pattern of Bacterial Meningitis Among Patients in Quetta, Pakistan

Introduction

Bacterial meningitis (BM) is a lethal infectious disease that persists as a substantial cause of morbidity and mortality. The antimicrobial drug resistance in BM pathogens poses a major threat to the community while raising challenges for clinicians. For the first time, we elucidate the incidence rate of BM and its drug resistance among the population of Quetta, Balochistan.

Methods

A cross-sectional study was conducted (from January 2018 to March 2021) among meningitis patients admitted to government hospitals in Quetta. The cerebrospinal fluid (CSF) specimen was collected and processed for microbiological and cytological analysis. Bacterial isolates were identified and confirmed using phylogenetic analysis of the 16S rRNA gene.

Results

We found 35.9% (321/894) confirmed cases of BM among the population of Quetta, Balochistan. The identified bacterial isolates comprised Streptococcus pneumoniae 14.7% (130/894), Staphylococcus aureus 6.9% (61/894), Neisseria meningitidis 5.7% (51/894), Haemophilus influenzae 2.5% (22/894), Escherichia coli 4.5% (40/894), and Klebsiella pneumoniae 1.9% (17/894). A high percentage in male patients of 20.8% (186/894) was identified as compared to female patients of 15.1% (135/894). Extreme age groups such as infants (age range: 1 month to 1 year) and adults (age range: 61 years to 99 years) with low immunity were critically affected by BM. Clinical parameters such as abnormal CSF appearance, pH, and high WBCs in BM patients with endocarditis as the underlying disease were significantly at elevated risk of fatal outcome. 16S rRNA gene phylogenetic analysis confirmed the evolutionary similarity of isolated strains with prevailing pathogenic strains in Asia. Furthermore, age was identified as a significant risk factor for clinical outcomes.

Conclusion

The majority of the identified BM patients belonged to rural areas with limited health-care facilities and paramedic staff. The high case fatality rate 11% demonstrates increased antibiotic resistance among BM isolates, thereby stimulating its devastation in underdeveloped regions. Timely detection and intensive treatment of BM may improve critical outcomes in patients.

Epidemiological Characteristics and Drug Resistance Analysis of Cerebrospinal Fluid Microbial Infections in Wenzhou Area

Objective

Central nervous system infections (CNSI) are serious diseases that endanger human health. Identifying pathogens and their susceptibility to antibiotics, and promptly using antibiotics under this guidance is essential for treatment. The purpose of this study is to investigate the pathogen characteristics of CNSI patients, which can help clinicians choose appropriate empiric antibiotic .

Methods

We retrospectively collected data on CNSI patients with cerebrospinal fluid (CSF) culture positive from 2012 to 2020, including demographic characteristics, laboratory data, pathogenic bacteria, and antimicrobial susceptibility test results.

Results

A total of 166 patients with 168 isolates out of 8188 patients were available for data analysis. Among the isolates, Gram-positive bacteria, Gram-negative bacteria and fungi accounted for 59.5%, 36.3%, and 4.2%, respectively. Among newborns, children under 12, and patients over 12, the most isolated strains were Streptococcus agalactiae (24/46, 52.2%), Streptococcus pneumoniae (21/68, 30.9%) and Staphylococcus epidermidis (10/54, 18.5%), respectively. Streptococcus agalactiae is more sensitive to linezolid and vancomycin. Streptococcus pneumoniae is more sensitive to vancomycin. Staphylococcus epidermidis is more sensitive to clindamycin and rifampicin. The sugar content in the CSF of Gram-negative bacteria of children ≤12 years old was significantly lower than that of Gram-positive bacteria (P<0.05).

Conclusion

We comprehensively studied the etiological characteristics and antimicrobial resistance patterns of positive cerebrospinal fluid cultures in Wenzhou City, Zhejiang Province from 2012 to 2020, which can provide valuable strategies for preventing pathogens and improving evidence-based treatment.

Pneumococcal vaccine implementation in the African meningitis belt countries: the emerging need for alternative strategies

Introduction: Besides meningococcal disease, the African meningitis belt (AMB) region is also affected by pneumococcal disease. Most AMB countries have introduced pneumococcal conjugate vaccines (PCV) following a schedule of three primary doses without a booster or a catch-up campaign. PCV is expected to help control pneumococcal disease through both direct and indirect effects. Whether and how fast this will be achieved greatly depends on implementation strategies. Pre-PCV data from the AMB indicate high carriage rates of the pneumococcus, not only in infants but also in older children, and a risk of disease and death that spans lifetime. Post-PCV data highlight the protection of vaccinated children, but pneumococcal transmission remains important, resulting in a lack of indirect protection for unvaccinated persons.Areas covered: A non-systematic literature review focused on AMB countries. Relevant search terms were used in PubMed, and selected studies before and after PCV introduction were summarized narratively to appraise the suitability of current PCV programmatic strategies.Expert opinion: The current implementation strategy of PCV in the AMB appears suboptimal regarding the generation of indirect protection. We propose and discuss alternative programmatic strategies, including the implementation of broader age group mass campaigns, to accelerate disease control in this high transmission setting.

Fletcher M, Koki Ndombo P, Boula A, Ashukem NT, Ngo Baleba M, Kingue Bebey RS, Nkolo Mviena EG, Tageube J, Kobela Mbollo M, Koulla-Shiro S, Madhi S, Njanpop-Lafourcade BM, Mohammad A, Begier E, Southern J, Beavon R, Gessner B. Impact of 13-valent pneumococcal conjugate vaccine on laboratory-confirmed pneumococcal meningitis and purulent meningitis among children ˂5 years in Cameroon, 2011-2018

BACKGROUND

The 13-valent pneumococcal conjugate vaccine (PCV13) entered Cameroon's childhood national immunization programme (NIP) in July 2011 under a 3-dose schedule (6, 10, 14 weeks of age) without any catch-up. We described the impact of PCV13 onserotype distribution among pneumococcal meningitis cases over time.

METHODS

We used laboratory-based sentinel surveillance data to identify meningitis cases among 2- to 59-month-old children with clinically-suspected bacterial meningitis (CSBM) admitted to hospitals in Yaoundé (August 2011-December 2018). Purulent meningitis cases had a cerebrospinal fluid (CSF) white blood cell (WBC) count ≥20 per mm3. Pneumococcal meningitis cases had S. pneumoniae identified from CSF, with serotyping by polymerase chain reaction. Years 2011-2014 were described as early PCV13 era (EPE) and years 2015-2018 as late PCV13 era (LPE) impact periods.

RESULTS

Among children hospitalized with CSBM who had a lumbar puncture obtained, there was no significant change from the EPE versus the LPE in the percentage identified with purulent meningitis: 7.5% (112/1486) versus 9.4% (154/1645), p = 0.0846. The percentage of pneumococcal meningitis cases due to PCV13 vaccine-serotype (VST) decreased from 62.0% (31/50) during the EPE to 35.8% (19/53) in the LPE, p = 0.0081. The most frequent pneumococcal meningitis VSTs during the EPE were 6A/6B (30%) and 5 (6%), and during the LPE were 14 (13.2%), 3 (7.6%), 4 (5.6%) and 18C (5.6%).

CONCLUSION

Four to seven years after PCV13 introduction, the proportion of pneumococcal meningitis due to vaccine serotypes has declined, mainly due to reductions of serotypes 6A/6B, 1, 19A, and 23F; nevertheless, PCV13 VSTs remain common. Because the analyzed surveillance system was not consistent or population based, we could not estimate incidence or overall impact; this emphasizes the need for improved surveillance to document further the utility of PCV13 immunization in Cameroon.

Analysis of Haemophilus species in patients with respiratory tract infections in Yaoundé, Cameroon

OBJECTIVES

To identifyHaemophilus species and characterize antimicrobial susceptibility of isolates from patients with respiratory tract infections (RTIs) in Cameroon.

METHODS

Isolates (n = 95) were from patients with RTIs obtained from two Hospitals in Yaoundé, Cameroon. Isolates were identified by biochemical assay, PCR-based method, MALDI-TOF and whole genome sequencing. Antibiotic minimum inhibitory concentrations were determined by E-test.

RESULTS

H. influenzae was the most prevalent species varying from 76.8% to 84.2% according to different methods. The isolates were mainly nontypable (n = 70, 96%). Three isolates of H. influenzae were capsulated (b, e and f). The isolates were genetically diverse and 40 unique sequence types were identified including 11 new ones. Resistance to ampicillin was observed among 55.3% (52/94) and 9% (14/52) produced TEM-1 β-lactamase. PBP3 mutations occurred in 57.7% of ampicillin resistant isolates (30/52). Eleven isolates were chloramphenicol resistant with 80% producing chloramphenicol acetyltransferase (8/10). Four Haemophilus isolates were rifampicin resistant with two mutations in rpoB gene. Five isolates were ciprofloxacin resistant and harbored mutations in the quinolone resistance determining regions of gyrA and parC genes.

CONCLUSION

H. influenzae isolates are highly diverse and show high levels of antibiotic resistance. H. influenzae serotype b is still circulating in the post-vaccination era.

Prevalence and antibiotic resistance profiles of cerebrospinal fluid pathogens in children with acute bacterial meningitis in Yunnan province, China, 2012-2015

Acute bacterial meningitis is still considered one of the most dangerous infectious diseases in children. To investigate the prevalence and antibiotic resistance profiles of cerebrospinal fluid (CSF) pathogens in children with acute bacterial meningitis in Southwest China, CSF samples from 179 meningitis patients (3 days to 12 years old) with positive culture results were collected from 2012 to 2015. Isolated pathogens were identified using the Vitek-32 system. Gram stain results were used to guide subcultures and susceptibility testing. The antimicrobial susceptibility of isolates was determined using the disc diffusion method. Of the isolates, 50.8% were Gram-positive bacteria, and 49.2% were Gram-negative bacteria. The most prevalent pathogens were E. coli (28.5%), Streptococcus pneumoniae (17.8%), Staphylococcus epidermidis (10.0%), Haemophilus influenzae type b (9.5%), and group B streptococcus (7.2%). In young infants aged ≤3 months, E. coli was the organism most frequently isolated from CSF (39/76; 51.3%), followed by group B streptococcus (13/76; 17.1%) and Streptococcus pneumoniae (8/76; 10.5%). However, in young infants aged >3 months, the most frequently isolated organism was Streptococcus pneumoniae (24/103; 23.3%), followed by Staphylococcus epidermidis (18/103; 17.5%) and Haemophilus influenzae type b (16/103; 15.5%). Antimicrobial susceptibility tests indicated that for E. coli isolates, the susceptibility rates to aminoglycosides ranged from 56.8% to 100.0%, among them, amikacin was identified as the most effective against E. coli. As for cephalosporins, the susceptibility rates ranged from 29.4% to 78.4%, and cefoxitin was identified as the most effective cephalosporin. In addition, the susceptibility rates of piperacillin/tazobactam and imipenem against E. coli were 86.3% and 100%. Meanwhile, the susceptibility rates of Streptococcus pneumoniae isolates to penicillin G, erythromycin, chloramphenicol, ceftriaxone and tetracycline were 68.8%, 0.0%, 87.5%, 81.3% and 0.0%, respectively. Gentamycin, ofloxacin, linezolid and vancomycin were identified as the most effective antibiotics for Streptococcus pneumoniae, each with susceptibility rates of 100%. It was notable that other emerging pathogens, such as Listeria monocytogenes and group D streptococcus, cannot be underestimated in meningitis.

Serotyping of Streptococcus pneumoniae based on capsular genes polymorphisms

Streptococcus pneumoniae serotype epidemiology is essential since serotype replacement is a concern when introducing new polysaccharide-conjugate vaccines. A novel PCR-based automated microarray assay was developed to assist in the tracking of the serotypes. Autolysin, pneumolysin and eight genes located in the capsular operon were amplified using multiplex PCR. This step was followed by a tagged fluorescent primer extension step targeting serotype-specific polymorphisms. The tagged primers were then hybridized to a microarray. Results were exported to an expert system to identify capsular serotypes. The assay was validated on 166 cultured S. pneumoniae samples from 63 different serotypes as determined by the Quellung method. We show that typing only 12 polymorphisms located in the capsular operon allows the identification at the serotype level of 22 serotypes and the assignation of 24 other serotypes to a subgroup of serotypes. Overall, 126 samples (75.9%) were correctly serotyped, 14 were assigned to a member of the same serogroup, 8 rare serotypes were erroneously serotyped, and 18 gave negative serotyping results. Most of the discrepancies involved rare serotypes or serotypes that are difficult to discriminate using a DNA-based approach, for example 6A and 6B. The assay was also tested on clinical specimens including 43 cerebrospinal fluid samples from patients with meningitis and 59 nasopharyngeal aspirates from bacterial pneumonia patients. Overall, 89% of specimens positive for pneumolysin were serotyped, demonstrating that this method does not require culture to serotype clinical specimens. The assay showed no cross-reactivity for 24 relevant bacterial species found in these types of samples. The limit of detection for serotyping and S. pneumoniae detection was 100 genome equivalent per reaction. This automated assay is amenable to clinical testing and does not require any culturing of the samples. The assay will be useful for the evaluation of serotype prevalence changes after new conjugate vaccines introduction.